1. Field of the Invention
The present invention relates to a method and apparatus for detection of reactive material in a test sample and more specifically to an apparatus for detecting and measuring luminescence which occurs as a result of interaction between reactive materials and reagents.
2. Description of Prior Art
A great number of organic, inorganic and living materials may be detected by luminescent reaction techniques. Adenosinetriphosphate (ATP) has been found in all forms of living organisms and the average amount of ATP contained in each species of cells is well defined, thus making ATP an indicator of living materials. By measuring ATP, the number and size of microbial cells can be easily computed. Enzyme contained in the firefly tail is used as an reagent for detecting ATP and consequently for detecting microorganisms. When the firefly enzyme extracted from the firefly tail, known as luciferase luciferin, is mixed with ATP from microorganisms, a reaction takes place with luminescent emission of light. The light emitted is proportional to the quantity of ATP provided sufficient enzyme is present for the reaction of the total ATP. Luminescence also occurs during interaction of microbial cells with reagents such as luminol-peroxide.
All known current methods for detection of bioluminescence and chemiluminescence used in pollution control and clinical applications are based on the use of a reaction chamber where sample and reagents are introduced for reaction and luminescent emission, a photomultiplier is used to detect luminescence, and a data recording unit records luminescence. These methods have limited resolution and sensitivity due to losses of light in transmission from the reaction chamber to the photo-detector, self-absorption of luminescence in the reaction chamber, and photodetector noise. The present invention is an improvement upon copending U.S. Pat. application Ser. No. 29,475, filed Apr. 17, 1970, and entitled "Luminescence Detection by Surface Reaction now U.S. Pat. No. 3,690,832," which disclosed a new way of detecting the reaction of very small volumes of sample and reagent by use of a surface reaction and of coincidence circuitry. The present invention is an improvement upon this method and provides a sample filtration unit and a reagent dilution unit. Furthermore, the function of the present invention as a scintillation detector has been improved by the use of liquid scintillator for greater instrument capability at a lower cost.